This invention relates to apparatus for providing physical comfort and safety during human pregnancy, and more particularly relates to a mattress which enables a pregnant woman to lie frontally downwardly on her abdomen throughout the prenatal period with a minimum of discomfort and a maximum of safety. Heretofore, it has generally been thought to be necessary to minimize, during the prenatal period, the amount of time pregnant women rest in a position where their distended abdomens are forced against a relatively non-compliant surface, for example that of a conventional mattress. Both the safety of the fetus and the comfort of the woman may be compromised when she is forced to lie frontally downwardly, particularly for extended periods of time during the latter stages of pregnancy. Accordingly, a need has arisen for a simply constructed, economical mattress upon which an expectant mother can lie in such a position for a desired length of time without suffering excessive physical discomfort or causing injury to the fetus.